Exploding grinding wheels represent an industrial hazard and are the source of an undesirable number of serious accidents with loss of productivity due to injury or death and product liability activity. Approaches to this problem in the past include manufacture of stronger wheels (including reinforcement), use of stronger and more effective guards, speed testing in the wheel manufacturer's plant and a "ring" test to detect the presence of large cracks at the time a wheel is put into service. When any brittle structure fails, the responsible crack at first grows slowly and then spontaneously upon reaching a critical size. This project is concerned with the development and evaluation of a technique for detecting a crack in the critical region of a grinding wheel (the bore) before it reaches critical size. This is done by running a fine helical conductor down the bore of the grinding wheel. When current flow is interrupted, this signals the presence of a subcritical crack or automatically shuts the machine down to prevent the crack from growing to the critical size which results in wheel "explosion". The project is concerned with several studies designed to result in improved grinding safety including a thorough evaluation of the aforementioned crack monitoring technique.